Sigma 77mm WR Weather Resistant Protector Filter is specifically designed for use with most of the SLR cameras and lens and perfect companion for outdoor as well as indoor photography. The protector filter is equally efficient for expert and immature photographer. The lens is made from high grade coated glass to repel water drops and resist smudging from fingerprints. The Sigma filter is an essential accessory for photography and fits to lenses that are threaded for 77mm filters. The filter protect front lens surface from dust, scratches, dirt and fingerprints. The glass material is treated to exhibit anti static properties to prevent microscopic dust from clinging to the front surface. The filter is lightweight and very easy to install & detach from lens.